: There is a paucity of information about the neuropathology of vascular dementia and the clinical features of vascular dementia and Alzheimer's disease among African Americans. African Americans have a high risk of stroke and may be a high risk of vascular dementia. The research is a continuation application of an NIA-funded study entitled "Studies of Dementia in the Black Aged: AD and MID" (July 1, 1991 - June 30 1996). The continuation application proposes to conduct longitudinal follow-up for three years (years 06-08) on the remaining African American study patients who were initially enrolled since 1991-1992 and who belong to one of the following two clinically diagnosed index case groups or control group, respectively: 1) Alzheimer's Disease (AD); 2) Dementia associated with stroke (referred to as vascular dementia or VaD); 3) Stroke without dementia (SWD). The primary objectives among the African American AD, VaD and SWD patients are to: 1) Accumulate enough standardized neuropathological observations, using CERAD criteria, on deceased cases and controls to validate clinical diagnoses of AD, VaD and SWD; 2) Collect standardized neuropathological observations that will explore and begin to: a) operationally define VaD neuropathologically by comparing neuropathological changes among the subgroup of VaD cases and SWD controls that do not have AD changes neuropathologically; b) operationally define mixed dementia (AD + VaD) neuropathologically by using factors that may be predictive of VaD from our VaD-SWD cases-control comparison (see 2A above) and standard neuropathological criteria for AD; 3) determine mortality rates and predictors of mortality among the cases and controls; 4) Determine the rate of decline and predictors of cognitive and functional decline among cases and controls; and 5) Profile and compare apolipoprotein E (APOE) alleles among cases and controls. Our observations, especially those that will explore the neuropathological operationally definition of VaD and mixed dementia (VaD + AD) will provide important preliminary information for the future development of a multi-center study to test the operational definition of VaD and study the natural history, treatment, and prevention of this disease.